Myiasis (myia means "fly" in Greek) is the infestation of body tissues of animals by the larvae of flies, commonly known as maggots. (1) Myiasis occurs mainly in the tropics and is associated with inadequate public and personal hygiene. It also occurs when people live in close proximity to animals Oral myiasis in human beings appears to be rare, and most cases have been reported from the developing countries, particularly in Asia. At least 86 different species of the fly Diptera can infect man with larvae that invade the skin and body cavities, such as the nasal fossae and ears, and cause odoriferous discharge. Eye involvement is secondary to nasal and ear lesions. Nasal myiasis also is common in patients with leishmaniasis. (2)
A 21 year old phocomeliac and mentally retarded male presented to the Department of Oral and Maxillofacial Surgery, D.A.V. (C) Dental College, Yamunanagar with severe maggots infestation of the oral cavity (Fig. 1). On examination, there were present hundreds of maggots in the anterior maxilla burrowing and causing the elevation of the whole buccal and palatal mucoperiosteum till the soft palate region (Fig. 2, 3).
A thorough debridement of the region was performed under local anesthesia by mechanically removing all the maggots with the help of an artery forceps (Fig. 4). This debridement was further aided by turpentine oil dressing which caused the maggots to move to a more superficial position for easy removal. In addition, the patient was given Tab Ivermecetin 12 mg. stat which is an antiparasitic and intravenous antibiotics were started to prevent any secondary infection. This surgical debridement with turpentine oil was done for 3 consecutive days twice daily till the site was completely free of maggots. The antibiotics were continued for seven days. The patient was discharged only after the complete elimination of maggots (Fig. 5, 6).
The classification of myiasis is based on the localization in the host body (dermal, subdermal, nasopharyngeal, internal organs and urogenital) or in, parasitological terms, on the type of host-parasite relationship (obligatory, facultative or pseudomyiasis). The myiasis can be obligatory, when larva in any of the stages of development needs living tissue, or facultative when maggots feed on decomposing matter or necrotic tissues. Obligatory myiasis is more harmful for the host, particularly mammals (including man). The infestation is most often subcutaneous and produces a furunculoid or boil-like lesion but can also occur in wounds and certain body cavities.
The flies whose larvae may be responsible for myiasis in man include the following groups:
Houseflies, Fannia canicularis (lesser house fly) and Musca domestica (house fly) may deposit eggs on skin wounds and give rise to myiasis. (3)
Family Calliphoridae (screw worms)
C.macellaria is a facultative parasite that may be responsible for secondary infestation of wounds. C.hominivorax larvae are obligatory parasites that feed on living tissue and can infest wounds but also penetrate unbroken skin. (4) Larvae of Chrysomyia bezziana, the old world screw worm, are obligatory parasites in wounds and infestation is seen especially in India and Africa. Larvae of members of the genera Phormia (black blowfly), Lucilia (greenbottle) and Calliphora (blue bottle) may also be secondary invaders of wounds in man.
Family sarcophagidae (flesh flies)
Sarcophaga occasionally infests wounds and necrotic tissue. (5) Wohlfahrtia magnifica, W.vigil and W.opaca cause infestation only in infants, as the larvae can not penetrate adult skin.
Cuterebra (rodent or rabbit botfly) only infrequently causes human myiasis. (6) Dermatobia (human botfly) like D.hominis causes cutaneous myiasis in man and particularly infests cattle. Myiasis caused by D.hominis is the most common cause of localized myiasis in the tropical new world.
Oestrusovis (sheep nostril fly) is a parasite mainly in sheep and goats, and Rhinoestrus purpureus is a parasite in horses, but both are occasionally responsible for myiasis in human beings. (7)
Oral myiasis is very rare, and was first described by Laurence in 1909. (8) In 1964, Scott reported only one case of oral myiasis in 120 human beings with myiasis in North America. According to Zeltser and Lustmann (1988), (9) 14 cases were reported until 1987, although they almost certainly did not consider some reports published in journals with small circulation. Myiasis is a worldwide phenomenon the prevalence of which is related to latitude and the lifecycle of various species of flies. The incidence is higher in tropical and subtropical zones of Africa and the Americas. The flies responsible for the condition prefer a warm and humid environment therefore myiasis is restricted to the summer months in temperate zones while it is all the year round in the tropics.
Methods of infestation in humans may occur in two ways, either accidentally with direct inoculation by the fly or by ingestion of infected materials such as meat. A direct infestation may be possible in cases the lesions are at the anterior mandibular or maxillary region however it would be difficult for the fly to infest directly the tissue of the molar region. An incidental ingestion of eggs was also reported in the literature as possible cause for intestinal lesions.
In the mouth, the fly usually lays larvae in the alveolus or in a periodontal pocket, which in about a week hatch into maggots. The larvae are 5 to 20 mm x 3 mm and as they grow, crawl into the tissue. The tendency to migrate increases as the larvae matures to pupation.
Oral myiasis can be primary or occasionally secondary to nasal involvement, when the maggots can penetrate to the paranasal sinuses or palate. Local factors such as halitosis caused by necrotic suppurating tissues can attract the flies. Mouth breathing during sleep, alcoholism, senility, mental retradation and hemiplegia may facilitate the development of oral myiasis. Some cases described in the literature were secondary to medical or anatomical conditions such as Cancrum oris, neglected mandibular fracture, cerebral palsy, mouth breathing, anterior open bite, incompetent lips and patients undergoing mechanical ventilation. Myiasis has also been described following teeth extraction. Oral myiasis is rare in healthy persons and is usually associated with poor individual hygiene.
Though the number of cases is small, we see that most infestation occurred in males probably because they tend to spend more time out-doors, and more frequently tend to neglect their oral hygiene when compared to females.
The diagnosis of myiasis is clinical and the treatment of oral myiasis is surgical debridement under local anesthesia. Debridement is curative, although a foreign body response may occur if parts of the larvae remain in the surgical site. Some authors have used local iodoform, ethylchloride, mercuric chloride, creosote, saline, or turpentine oil and systemic butazolidine or thiobendazole. Further some articles described methods of occlusion and suffocation used in the skin infestation. Application of such materials forces the aerobic larvae into a more superficial position where it is possible to remove them easily with less damage to the tissues. (10) But these methods are not easily applicable in the oral cavity. Hence thorough lavage and surgical debridement are the treatment of choice for cases involving the oral cavity. This condition can be prevented by proper maintenance of personal and environmental hygiene especially taking care of necrotizing and fungating wounds by cleaning, using topical metronidazole and palliating radiatons if required.
It can be concluded that oral myiasis although a rare condition is still found more frequently in tropics. It occurs more commonly in either habitually neglected mouth or if the patient is medically compromised. Thorough mechanical debridement is although curative but overall prognosis of medically compromised patient is poor.
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(1.) James MT. The flies that cause myiasis in man. U.S. Department of Agriculture Miscellaneous. Publications No. 631. Washington: U.S. Government Printing Office, 1947.
(2.) Zumpt F. Myiasis in man and animals in the Old World. London: Butterworths, 1965.
(3.) Logan JCP, Walkey M. A case of endemic cutaneous myiasis Br J Dermatol 1964, 76, 218-22.
(4.) Macias EG, Graham AJ, Green M et al. Cutaneous myiasis in South Texas. N Engl J Med 1973, 291, 1239-41.
(5.) Arbit E, Varon RE, Brem SS. Myiatic-scalp and skull infection with Diptera Sacrophaga: case report. Neurosurgery 1986, 18, 361-2.
(6.) Hodges FJ. Cutaneous Cuterebra myiasis. Am J Dis Child 1955, 90, 202-4.
(7.) Omar MS, Das AB, Osman NI. External ophthalmomyiasis due to the sheep nostril botfly larva Oestrus ovis in Saudi Arabia. Ann Trop Med Parasitol 1988, 82, 221-3.
(8.) Laurence SM. Dipterous larvae infection. Br. Med J 1909, 9, 88.
(9.) Zeltser R, Lustmann J. Oral myiasis. Int J Oral Maxillofac Surg 1988, 17, 288-9.
(10.) Meinking TL, Burkhart CN, Burkhart CG. Changing paradigms in parasitic infections; common dermatological helminthic infections and cutaneous myiasis. Clin Dermatol 2003, 21, 407-16.
Kirti Chaudhry , Sukhvinder Bindra , Vikas Sharma , Naveen Chhabra , Shruti Chhabra 
Senior Resident  Deptt Of Oral And Maxillofacial Surgery Govt Medical Collega And Hospital, Sec-32. Chandigarh
Reader  Deptt of oral And Maxillofacial surgery Kamineni Institute of Dental Sciences Nalgonda
Senior Lecturer  Associate Professor  Reader 
Deptt of oral And Maxillofacial Surgery Dav(c) Dental College Yamunanagar
Received: October 9, 2010
Review Completed: November 12, 2010
Accepted: December 16, 2010
Available Online: April, 2011
Email for correspondence: firstname.lastname@example.org
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|Title Annotation:||Case Report|
|Author:||Chaudhry, Kirti; Bindra, Sukhvinder; Sharma, Vikas; Chhabra, Naveen; Chhabra, Shruti|
|Publication:||Indian Journal of Dental Advancements|
|Date:||Jan 1, 2011|
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